Prepare v2015.04-rc4

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/Makefile b/Makefile
index 9747bd2..1b3ebe7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 VERSION = 2015
 PATCHLEVEL = 04
 SUBLEVEL =
-EXTRAVERSION = -rc3
+EXTRAVERSION = -rc4
 NAME =
 
 # *DOCUMENTATION*